28 June 2008

10 Audacious Ideas to Save the Planet

10 Audacious Ideas to Save the Planet Popular Science June 13, 2008

To rescue the Earth, we need bold engineering ideas that go beyond simple recycling
Making a dent in the climate crisis is going to take more than solar panels and recycled toilet paper. Scientists are finding ever more creative ways (pig pee! DIY tornadoes! mini nuclear reactors!) to clean up the Earth
Beaming Electricity from Space
The Vision Launch giant solar panels into orbit and send limitless clean energy back to Earth
The Plan By 2030, Japan hopes to pull its power from the heavens instead of from polluting coal plants.
The idea is to send satellites into geostationary orbit above the equator, where they will unfurl 1.5-mile-long solar arrays and soak up the sun 24 hours a day. Transmitters mounted on the satellites would convert the solar energy into microwave energy and beam it down to terrestrial receiving stations. Equipped with massive antennas measuring two miles across, each station would produce one gigawatt of electricity—enough to power 500,000 homes. That’s twice as much as a typical coal-fired plant, and without any of the greenhouse emissions.
Putting solar panels in space has one obvious advantage: It’s never cloudy 22,000 miles up. On average, there’s 8 to 10 times as much sunlight available in space as there is on Earth, where atmosphere and weather get in the way. Now, with satellite launch costs dropping (about five thousand dollars per pound today, versus $12,000 per pound a decade ago) and energy bills rising (already double what they were in 2005), researchers are finally warming to the idea.
Later this year, in fact, the Japan Aerospace Exploration Agency (JAXA) plans to test the idea on the ground, blasting a microwave beam some 170 feet to a 6.5-foot-wide rectenna, a type of receiver that converts microwaves into DC electricity. Not as glamorous as beaming rays from space, but it’s a vital first step.
Potential Uh-Ohs One frightful but improbable scenario is that the microwave beam misses the receiving antenna and fries something on Earth’s surface. Like a village. To mitigate that risk, JAXA scientists are developing an automated detection system that turns off the microwave beam if the satellite drifts out of line.
ETA JAXA aims to launch its first energy-beaming satellite into orbit by 2013, with a network of powersats that feed energy directly into the grid to follow by 2030.—Rena Marie Pacella

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